Introduction

As patients with end-stage heart failure are living longer and increasing in numbers; left ventricular assist devices (LVADs) are becoming more common as a therapeutic treatment option when conventional medical therapy has reached its limit. These devices are being used as either a bridge to transplant or as destination therapy. Many patients with advanced heart failure that require LVAD support have some degree of right ventricular (RV) dysfunction. It is estimated that RV failure (RVF) occurs in approximately 10–40% of LVAD recipients [1–3]. Aggressive treatment of this RV failure is paramount to a successful outcome after LVAD implantation.

Severe RVF is manifested by an increase in central venous pressure (CVP), hepatic, and renal dysfunction, and low LVAD flows due to decreased preload for the device [4]. This is associated with increased peri-operative mortality, prolonged hospital stay, and poor quality of life [5, 6]. Treatment of RVF includes inotropes, nitric oxide (NO), and mechanical support. Continued high dose inotropes can lead to bowel and limb ischemia along with increasing myocardial oxygen demand [7]. RVF that continues to worsen despite high dose ionotropic medical therapy may require a RV assist device (RVAD).

There are two types of temporary RVAD (t-RVAD) devices. The first is placed in the operating room through an open sternotomy where blood is drained from the right atrium and returned into the pulmonary artery (PA) through cannulas placed directly in the right atrium and the PA [7]. This type of approach requires reoperation an additional sternotomy when the t-RVAD needs to be explanted after RV recovery (Figure 1). Another t-RVAD is a Protek Duo^® cannula (Figure 2): a dual lumen single cannula that is percutaneously inserted into the right internal jugular vein and is advanced under fluoroscopy or direct visualization into the PA [8]. The advantage of this percutaneous t-RVAD is that it can be removed at the bedside and does not require reoperation or repeat sternotomy. The purpose of this study is to determine in those patients with refractory RVF that require RV mechanical support after LVAD implantation; how does the new percutaneous Protek Duo^® RVAD device compare to the traditional “open” t-RVAD which requires an additional sternotomy for removal.

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Figure 1. 

Open RVAD placement in the operating room after HeartWare LVAD implantation. RVAD: right ventricular assist device; LVAD: left ventricular assist device

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Figure 2. 

Percutaneous RVAD placement with Protek Duo^® in the operating room after HeartWare LVAD implantation. RVAD: right ventricular assist device; LVAD: left ventricular assist device

Materials and methods

This was a retrospective, single center, observational study. After Institutional Review Board approval, we identified 28 patients between 2013–2019 that required a t-RVAD device after LVAD implantation. The LVAD patients were identified by using a master list of all LVAD patients implanted at our institution that was kept by the LVAD coordinators in the cardiology heart failure department. We then sub-divided those patients that had the diagnosis of RVF. We then further subdivided those RVF patients to those who received t-RVAD support by using the billing code of veno-venous extracorporeal membrane oxygenation (VV-ECMO); as these patients were billed for VV-ECMO management as they all had an oxygenator on the t-RVAD device. Inclusion criteria included: Age > 18 years, primary LVAD implantation, and t-RVAD after LVAD implantation. Exclusion criteria included second LVAD implantation and late implantation of t-RVAD, which was identified as greater than 72 h for placement of RVAD after the initial LVAD operation. This excluded 6 patients from our analysis as t-RVAD support was placed greater than 72 h after LVAD implantation. The primary endpoint was one-year survival. Secondary endpoints were evidence of cardiac tamponade, other bleeding, requirement of blood products (red blood cells, fresh frozen plasma, and platelets), need for and duration of NO therapy, duration of t-RVAD support, renal replacement therapy (and duration), duration of mechanical ventilation, liver dysfunction, need for and duration of vasopressors, discharge alive from the intensive care unit (ICU), ICU length of stay, hospital length of stay, and the need for heart transplantation.

The 22 t-RVAD patients were placed into two groups: RVAD with a percutaneously placed Protek Duo^® cannula or “open” t-RVAD—which was placed through open sternotomy and required a return to operating room for removal. A total of 8 patients were identified requiring Protek Duo^® support and 14 patients required “open” RVAD support after new LVAD implantation (Figure 3).

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Figure 3. 

Flow chart of LVAD implantations requiring RVAD support. LVAD: left ventricular assist device; RVAD: right ventricular assist device; RV: right ventricle; IJ: internal jugular; RA: right atrium; PA: pulmonary artery

Results

Discussion

RV failure is the most common complication after implantation of a left ventricular assist device. High dose inotropes and vasopressors may be necessary to help the right ventricle to provide enough preload for the LVAD achieve goal flow. However, high dose inotropes after cardiac surgery has been associated with many complications including limb and bowel ischemia. In order to limit this complication from high inotropes, a RV assist device may be used. The classic method of “open” cannulation is achieved by placing two cannulas—one in the right atrium and other in the PA after cardiotomy and LVAD placement. The downside to this is re-sternotomy is required for t-RVAD explanation. The other is now a percutaneous dual lumen single cannula that is placed in the right internal jugular vein to the PA. This is known as the Protek Duo^® cannula [4, 9–11], which can be removed at bedside after RV recovery.

In this retrospective analysis of outcomes following temporary RVAD (t-RVAD) implantation, “open” vs. Protek Duo^® RVAD, 22 patients, with mean age of 55.7 and mean LVEF of 17.1%, met the inclusion criteria. Baseline characteristics amongst the two groups were similar aside from albumin level and PaO₂/FiO₂ ratio, which were both higher in the Protek Duo^® group (Table 1). Even though it was not statistically significant, all most all “open” RVAD patients were INTERMACS 1. There was also a difference in timing of RVAD implantation: most “open” t-RVADs were implanted immediately after cardiac bypass in the operating, versus only a quarter in the Protek Duo^® group. Consequently, in the Protek Duo^® group more than half of the RVAD implantations occurred between 48–72 h; where as in the “open” t-RVAD group there was only 1 case of delayed RVAD implantation (Table 1). In both groups, 48 h after LVAD implantation the hemodynamics and vasopressor use were similar, however the “open” t-RVAD group had lower platelet count and greater need for mechanical ventilation (Table 2). The average time on t-RVAD support was similar between both groups. There were significant differences in the total number of days of mechanical ventilation and the Protek Duo^® group had overall less use of blood products. There was also no difference in MVP as the goal was to keep it between 60–70 mmHg to reduce the influence of afterload that could be impairing the LVAD function. Also, the CVP for both groups was elevated above normal to ensure adequate preload was given to the RV to help with function. There were no differences in ICU length of stay, discharge alive from the ICU, hospital length of stay, or one-year survival (Table 3).

There was no difference in long term outcomes when RVAD was implanted immediately (more likely with “open” t-RVADs) or in the delayed strategy (implantation > 48 h post LVAD, more common in the Protek Duo^® group). This suggest that use of a Protek Duo^® as strategy for refractory RV failure is a viable option, and a short-term trial of high dose inotropes could be used to help with RV recovery without immediate mechanical support. Because the Protek Duo^® is a less invasive method of RV support, there should hypothetically be less complications. This was captured in this study by the use of far less use of blood products in the Protek Duo^® group, even in the setting of an equal chance of bleeding events between the two groups. This observation may have been driven by the fact that the “open” t-RVAD requires repeat sternotomy for RVAD explanation; whereas Protek Duo^® removal is a bedside procedure. Based on these findings, a viable strategy for RV failure after LVAD implantation could allow for use of high dose inotropes for 48 h and if no RV recovery is observed, a Protek Duo^® could be placed percutaneously for long term mechanical RV support.

We determined that there was no decrease in effectiveness in RV support by using the Protek Duo^® vs. “open” t-RVAD, as seen by no difference in long term outcomes (ICU/hospital length of stay and one-year survival) as well as amount of vasopressor/inotropic/NO use post-RVAD implantation. Average days under mechanical ventilation was greater in the “open” t-RVAD group, but this cohort also had a lower PaO₂/FiO₂ ratio on day of LVAD implantation. One major advantage of the Protek Duo^® cannula is that it can be taken out at bedside; thus, there is no need for a reoperation for removal. This leads to less bleeding and infection risk, and allows for earlier extubation in the ICU after the operation. The delay in placement of the Protek Duo^® with no difference in outcome allow clinicians to try to manage the RV failure medically after LVAD placement, and to determine if mechanical RV support is absolutely necessary. This will lessen the need for mechanical right heart support, which can increase risk of bleeding and infection no matter which method of t-RVAD strategy is utilized. [10, 11–15].